Electric lamp and lamp-holder.



No. 697,458; Patented Apr. l5, I902. H. J. nuwsme.

ELECTRIC LAMP AND LAMP HOLDER.

(Application filed Oct. 28, 1901.)

(No Model.)

H'ulllllllllllllllllllllllllllllllllfll WIIIIIIIllllllllIIIIIIIIIIIIIIIIIIH:

UNITED STATES PATENT OFFICE.

HERBERT JOHN DOWSlNG, OF LONDON, ENGLAND.

ELECTRIC LAMP AND LAMP-HOLDER.

SPECIFICATION forming part of Letters Patent No. 697,458, dated April 15, 1902.

Application filed October 28, 1901. Serial No. 80,282. (No model.)

To all whom, it may concern:

Be it known that I, HERBERT JOHN Dow- SING, a subject of the King of Great Britain, residing at London, England, have invented certain new and useful Improvements in and Connected with Electric Lamps and LamplIolders; and I do hereby declare the following to be a full, clear, and exact description of the invention, such as will enable others skilled in the art to which it appertains to make and use the same.

This invention relates to improvements in and connected with incandescent lamps and holders therefor, whereby perfect electrical contact is insured between the lamp and the holder, and thelamp maybe connected or disconnected with the minimum amount of movement of the parts of the holder itself.

In the accompanying drawings, Figure 1 is an elevation, and Fig. 2 a longitudinal section, of a portion of a lamp and its holder fitted in accordance with my invention. Fig. 3 is a plan View of the interior of the holder shown in Figs. 1 and 2. Fig. i is a similar View to Fig. 1, but illustrating a slight modification. Fig. 5 is an end view of the lamp shown in Fig. 4. Fig. 6 is a similar view to Fig. 2, butillustrating a further modification; and Fig. 7 is an end view of the lamp shown in Fig. 6.

Similar letters of reference relate to like parts in all the figures of the drawings. Y

Referring to Figs. 1, 2, and 3, a is the stem of the lamp, furnished with two radial projections or pins 1), preferably diametrically opposite to one another in the usual manner, as shown. The outer end of the lamp-holder is made in the form of a tubular socket c and is adapted to receive the stem a of the lamp. jj are two spring split pins mounted in and projecting from the insulating-block k in the lamp-holder and connected with the conducting-wires Z in a manner well understood in connection with this kind of apparatus. The spring split pinsjj are adapted to enter corresponding tubes or holes in the stem a of the lamp, thereby securing a sliding metallic electrical contact between the parts. The exterior of the tubular socket c is furnished with a screw-thread d to receive the screwed collar 6 for retaining the lamp-shade in place or for clamping the holder in position in a stove, for example. This external screw cl also serves to receive an internally-screwed sleeve f, somewhat resemblingthe sleeve of a pipe-union and havinga groove or recess formed on its internal circumference. The outer end of the tubular socket c and also the outer end of the internally-threaded sleeve f have notches h and 2' formed therein, which notches correspond in position to the radial pins or projections 11 on the stem 0. of the lamp. The said stem is pressed into the tubular socket 0, its two pins 1) entering the before-mentioned notches h and 11, formed in the walls of the socket c and screwed sleeve f, the latter being turned into such a position as to cause its notches 'i to coincide with the notches h in the tubular socket c. As soon as the lamp is in place the screwed sleeve f is turned until its notches 2' no longer coincide with the notches hin the walls of the tubular socket c, the ends of the radial pins or projections b on the stem a of the lamp entering the before-mentioned groove or recess 9 on the internal circumference of the screwed sleeve f, and the lamp is thus held securely in place. It will be understood that the rotation of the screwed sleeve f will also tend to draw the stem of the lamp, by means of its radial pins or projections 12, farther into the tubular socket c of the holder, and thus insure perfeet electrical contact between the parts.

In the modification illustrated in Figs. 4 and 5 the radial pins or projections 19 on the stem at of the lamp and the screwed sleevef are dispensed with, the lamp being retained in position and electrical contact insured by the frictional grip of the spring split pinsjin the holes 'm of the stem aof the lamp, and in some cases I supplement the frictional grip of the spring split pins j by the addition of spring devices in connection with the holder itself.

Figs. 6 and 7 illustrate a modification of the stem at of a lamp and its holder in which the well-known form of bayonet-joint may be employed for connecting the lamp-holder to the stem a of the lamp. In this case the spring split pins j are not pressed into circular holesas in Figs. 2 and 4, for examplebut they are brought into sliding and spring contact with segmental contact-plates n, in which tapered grooves 13 are formed and into which the spring split pins 70 slide and against the Walls of which the said pins may be more or less tightly wedged as the stem 01, of the lamp is being adjusted in the bayonet-slot of the holder.

It will be understood that the spring split pinsj are fixed in the insulating-block k, the only spring action being due to the tendency of the split ends to separate when free or be closed together when forced into a hole 071 or a groove p.

I claim I11 combination, a tubular lamp-holder, or socket, a pair of split spring-pins Within the 

